Forging units



Aug- 22, 1967 C. HUTSON ETAL 3,336,787

FORGING UNITS Filed May 7, 1964 6 Sheets-Sheet l A g x r.\\. .A s W INNEN-r 5 AT1-0am 5v5 C. HUTSON ET AL Aug. 22, 1967 FORGING UNITS 6 Sheets-Sheet 2 Filed May '7, 1964 Aug. 22, 1967 C. HUTSON ETAL FORG ING UNITS 6 Sheets-Sheet 5 Filed May '7, 1964 .w MQ@ s www VM L voo am m NNN mu/K v MHH M I T wf H. M v Q s Aug. 22, 1967 c. Hu'rsoN ETAL 3,336,787

FORGING UNITS Filed May '7, 1964 6 Sheets-Sheet 4 Bv Mmmm Aug 22, 1967 c. HUTSON ETAL. 3,336,787

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United States Patent O 3,336,787 FORGING UNITS Colin Hutson and Keith Knowles, Sheffield, England, assignors to The British Iron and Steel Research Associ- The present invention relates to a forging press, particularly although not exclusively suitable for operations such as cogging metal ingots from larger to smaller sizes.

In the past, while it has been possible to accelerate the movement of the tool-bearing member pr members which impact and/or squeeze a workpiece, the overall forging time has not fallen in proportion, mainly because the speed at which the -machineryfor manipulating the workpiece in preparation for successive forging operations has not increased to match the improved performance of thesaid member or members. Generally speaking such manipulating machinery has included apparatus for linearly moving the workpiece between the forging tools, for lifting the workpiece to re-align its axis after each forging bite, and to rotate the workpiece about the axis to expose different faces to the tools. The inertia of machinery capable of performing these functions has proved a limiting factor as regards accelerating the manipulation of the workpiece, and for shortening the overall time for forging operations.

It is an object of the present invention to provide an improved forging press, and, according to the invention, there is provided a forging press comprising a framework, a pair of press members located within said framework and at least one of which members is reciprocable relative to the other to effect workpiece forging operations, and manipulating means connected to said framework and operable to effect workpiece manipulating operations.

The press according to the invention has particular advantage when so adapted that both of the tool-bearing members reciprocate relative to a fixed workpiece forging axis, since in such case there is no necessity to move the workpiece perpendicularly relative to such axis after a squeeze to effect a bite, that is longitudinal workpiece movement, as is the case when one tool is fixed.

Where the forging axis is fixed as described, it is important that the tool-bearing members are controlled to act equally on both sides of the workpiece, since otherwise the workpiece would be deflected from the working line.

In another aspect, therefore, the invention provides a forging press as described above, and control means operable upon the means for causing movement of the press members for controlling the position and/or speed of such members in accordance with their distance from the said line.

lThe reciprocable members will normally be in the form of fluid actuable cross-headsv provided with supports on their inwardly directed faces for the various tools used in forging. Also, the cross-heads are preferably provided with a number of hydraulic rams having dimensions selected to give a required range of operating speeds, intensities and -strokes for the cross-heads. The cross-heads may be reciprocated in any direction, but particular advantages accrue in respect of ground area, height and tool changing considerations where the reciprocation is horizontal.

The workpiece may be propelled towards and away from required forging positon along the forging axis between the cross-heads by means of longitudinal manipulators each comprising an element having a convex gripping rsurface which can be urged into gripping contact with the workpiece, and then turned through a selected angle in a plane passing through the forging axis, whereupon, in effect, the workpiece rolls over the gripping surface. The convex surface may be a circularly curved surface such as the surface of a roller or of a segment of a cylinder, and the elements may be operable by rams, one ram being provided for urging the surfaces into gripping Contact with the workpiece, and another ram being provided to impart the angular turning movement for propelling the workpiece. One or more of such longitudinal manipulators may be disposed on each side of the forging axis.

In order that the workpiece may be rotated about its longitudinal axis in order to expose various parts of its peripheral face to the forging tools, rotational manipulation means are provided as a feature of the forge according to the invention.

In one form, the rotational manipulator means comprises a pair of spaced grip members which can be operated by fluid actuated rams to move towards a workpiece disposed therebetween in order to position and/or grip the'workpiece. The ends of each grip bar are disposed in guides which are secured in a frame mounted in bearings for rotation relative to a fixed support. Preferably, the axis of rotation is arranged to coincide with the forging axis, and the operation of the rams is such as to ensure that the grip members are disposed as nearly as possible symmetrically relative to the said line: this presents the advantage that the longitudinal axis of the workpiece when positioned or gripped by the grip members is substantially coincident with the forging axis.

Where the workpiece is short in comparison with the Width of the press members, it is desirable to be able to support the workpiece in a required position for forging by means which can be removably disposed from between the press members. According to a feature of the invention, such means may comprise a roller table which is narrower than the anticipated workpiece. The roller table is arranged parallel with the forging axis, and means, such as a fluid actuable ram, are associated with the roller table for adjusting the position thereof so that the workpiece can be positioned as desired relative to the forging axis.

As a short workpiece is progressively forged, its width decreases and a corresponding increase in length takes place, until the workpiece length exceeds the width of the press members. At such time, the workpiece may advantageously be supported at the end or ends protruding from between the members, and with this in View, a roller table extending generally parallel with the forging axis may be provided on each side of the path of the press members. When the workpiece is thus supported, the roller table between the press members may be withdrawn.

The roller tables on each side of the path of the members may comprise a roller which can be moved in its axial direction, that is, at right angles to the forging axis, so that the workpiece may be moved in the said axial direction for so-called side shift positioning.

Where the members reciprocate along a generally horizontal path, .a pit may be provided beneath the path for receiving tools and tool changing equipment.

The movement of the members andthe several manipulation means may be subject to a control system adapted to ensure that the members and manipulation means are actuated according to a preselected progra-mme.

For a better understanding of the invention, a forging unit according to the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIGURE l is a perspective view of a forging press unit having longitudinal and rotational manipulation means for a workpiece,

FIGURE 2 is a part cross-section view of the unit of 3 FIGURE 1 taken along the forging axis and between the press members thereof,

FIGURE 3 is a part longitudinal section of the unit of FIGURE 1 taken transverse the forging axis and through a press member thereof,

FIGURE 4 is an enlarged section view of one of the longitudinal manipulators of FIGURE l,

FIGURE 5 shows schematically the synchronising control means for the press members of FIGURE l, and

FIGURE 6 illustrates stages in the operation of the arrangement of rams in the press members of FIGURE 1.

In FIGURE 1, the forge unit comprises a double acting horizontal press having two outer fixed crossheads 12 of fabricated steel construction, connected by four tie-bars 13 of generally rectangular section. A cross-bar 14 spans the upper tie-bars. Movable crossheads 15 are connected to and reciprocable by means of three pistons 16, 17, 18. The complementary cylinders for these pistons are located in the fixed crossheads 12.

By selection of a combination of these pistons three different power strokes may be obtained, that is to say, the central piston 16 may be operated alone, the outer pistons 17 and 18 may be operated together, or all three pistons may act together.

The movable crossheads 15 are formed with anges 20 by which they are supported on the lower tie-bars 13, so that they can slide along the tie-bars on renewable wear strips. The inner corner of tie-bar 13 is cut away as at 21 to -avoid direct contact at the corner of the corresponding bearing surfaces in the crossheads 15.

Attached to the inner faces of the movable crossheads 15 are the forging tools which are located in vertical slideways and secured by a detent mechanism.

Three roller tables 22, 23, 24 are provided for supporting an ingot 55 to be forged. The central support table 22 is narrower than those outside the press structure and enables the shorter heavier ingots to be supported during the initial forging passes. This table is retractable so that as the stock becomes smaller in section and longer it is supported on the outer tables 23, 24 only.

Each ingot supporting table is of variable height in order to accommodate ingots of various dirnensionsand to maintain the ingot axes in a constant vertical position during forging in accordance with changing ingot depth. A stock height measuring device operating within the press structure controls the height of the outer roller tables.

For this purpose the outer roller tables are supported on hydraulic rams at their ends nearer the press members and are pivotally supported at their other ends, as shown in FIGURE 2, whereby the tables are of adjustable slope. Alternatively the outer tables may be adjustable in height at both ends.

Two pairs of longitudinal manipulators generally indicated by 41 are incorporated in the unit situated one on each side of the press on the ingot axis. Each device consists of an upper and lower ingot gripping element 25, having a part cylindrical gripping surface. As shown, each gripping element is a segment of a cylinder. However these may also be rollers or other convexly curved elements.

Referring now to FIGURES 1 and 4, each gripping element is supported by a stern 26 slidable in a slidew-ay 27 and is vertically reciprocable by a variable stroke piston and cylinder assembly 28. Oil feed passages 51 are provided to supply oil for example ata pressure of 2000 p.s.i. to ldrive the cylinder 28.

Each gripping element 25 .is pivotable on spindle 50 about an axis normal to the axis of an ingot 55 to be forged, and each such element is connected to the movable part of a double-acting variable stroke rotary hydraulic actuator the relatively stationary part of which is connected t0 the stem 26 to move vertically therewith. Operation of this actuator causes the gripping member to rotate.

The action of such longitudinal manipulators 41 in moving an ingot rapidly during the ingot free time between presses, is for the stems 26 to be propelled along the slideways by cylinder 28 until the gripping elements 25 contact the ingot. The gripping members are rotated by means of the rotary actuators 30 so that the ingot is propelled longitudinally by an amount proportional to the actuator rotation. This amount may be varied according to the required longitudinal incremental movement of the ingot between each press stroke.

The face of the gripping members may be shaped either linear transversely of the face and forging axis, or V-shaped in section to accommodate square or round shaped ingots.

A form of rotational manipulator, generally indicated by 47, is shown in FIGURES l, 2 and 3.

This assembly comprises the devices for ingot rotation, ingot centering and ingot guiding. Two such units are incorporated one Ion each side of the press, each containing four gripping devices disposed symmetrically around the forging axis.

To operate the gripping devices 31 the rotational drive 58 is locked in position, the grip drive motor 32 then rotates the gear nut 33 through gears 34 and 35 propelling the screwed grips radially with respect to the ingot axis. The direction of movement of the grip is dependent upon the direction of rotation of the drive motor. The grips are prevented from rotating by means of a key 63.

To rotate the ingot manipulator the grip drive motor 32 is disengaged by means of the clutch 36. The carrier 46 containing the four grips is rotated on the bearings 57 by the rotational drive motor 58 through gears 60 and 61. Positional accuracy can be provided by means of a detent mechanism.

As shown more particularly in FIGURE 3, a vertical tool changing mechanism, generally indicated by 42, is situated in a tool pit 43 beneath floor level. For changing a tool, such as tool 40, each movable crosshead 15 is fully retracted. Two hinged plates (not shown) which normally form part of the floor between the xed crossheads 12 aire opened into a vertical position directly beneath the tools. A slide on the underside of each plate interconnects the tool slide 44 on the movable crossheads with the tool changing mechanism 42.

A vertical ram assembly 45 which forms part of the tool changer is raised to engage the tool and extracts the tool from the crosshead. The tool is then lowered into a magazine 62 which is indexed so that the next selected tool is positioned beneath the crosshead for insertion by the vertical ram assembly 45.

A system of spring loaded or hydraulic cylinder locking devices retain the tool on the movable crosshead 15.

By this arrangement any combination of tools can be selected and both right and left hand tools can be changed simultaneously while an ingot remains within the press structure.

FIGURE 5 shows the general arrangement of a hydraulic circuit which may be applied t0 the movable crossheads 15 to synchronise their movements, so that their positions from the press centre line are maintained equal.

The circuit operates on the two separate fluid delivery sets for driving the `crossheads 15. The delivery sets basically comprise substantially identical assemblies of rams 65, 65a fed through valves 66, 66a from pumps 67, 67a driven by motors 68, 68a. The outputs from the pumps 67, 67a are connected through a small variable delivery pump 70, which can operate to draw oil from any one supply line to a ram assembly and supply it to the supply line for the other ram assembly.

The ram assemblies 65, 65a are selected to be matched as nearly as possible in performance, so that any correction of position of the crossheads 15 can be achieved by small quantities of oil. In consequence, the variable delivery pump 70 can be of relatively small capacity, say, 5% to 10% of the capacity of pumps 67.

Two digitisers 71, 71a measure the distances x, y of the crossheads 15 from the forging axis, and feed an error signal (1c-y) to a torque motor 72. Alternatively, one of the digitisers 71, 71a may be utilised to indicate the position of a crosshead 15, while the other of the digitisers provides a synchronisation signal.

In order to eliminate error signals due to stretching of the press, the digitisers 71, 71a are each mounted on a supporting beam which is fixed at one end at the centre of the press, and slidably attached to the fixed crossheads 12. The distance between the digitisers and the centre of the press does not thus alter even if the distance between fixed crossheads 12 changes. If the two crossheads 15 are perfectly synchronised as far as speed and distance from the forging axis are `concerned this error signal will be zero. If however, the signal is not zero the torque motor 72 will operate to cause a servo valve 73 to be actuated which through motor 74 controls the variable pump 70. The variable pump 70 will draw oil from the leading side and pass itto the lagging side until the error signal is corrected to Zero.

If the error signal exceeds a predetermined value, the flow of oil from that one of pumps 67 connected to the leading side may be diverted to a storage tank so that the lagging side may achieve synchronisation.

FIGURE 6 shows schematically in more detail the operating arrangement for rams 65, 65a for actuating crossheads 15, each such arrangement, only one of which is shown, comprising a single-acting ram 80, and on each side thereof two double-acting rams 81 having an annular piston face area 82 half the area of the full piston face area 82a, while the latter area is one half of the full piston face area of ram 80.

FIGURE 6 is in fact in four parts of which (a) illustrates, for the sake of example, the left-hand side crosshead 15, and demonstrates the directions of flow of oil during the return stroke of crosshead 15 from its forging position. It will be seen that both sides of the pistons of rams 81 contain oil at all times. Due to the relatively small area of the annular pistons 82, the return stroke can be executed at a relatively high speed.

In FIGURE 6(b), the crosshead 15 is moving forwards towards the forging position. The oil displaced from the annular cylinders of rams 81 augments the delivery from pumps 67 to ram 80. Thus the crosshead 15 moves forward at a relatively high speed.

When resistance to forward movement such as the resistance due to the contact of the tools on crossheads 15 with the workpiece causes the oil pressure to rise in ram 80, the appropriate valve means are operated to eect the connections of FIGURE 6(c) where the flow of oil from the annular cylinders of rams 81 are diverted to an exhaust line, which may lead to for example, a surge tank (not shown). Since the contained volume of these annular cylinders is one half the volume of the rams 81, the crosshead 15 continues to be driven forwardly now at half its previous speed.

As the resistance to forward movement increases further, the appropriate valve means operate to effect the arrangement of FIGURE 6(d) at a predetermined resistance. The oil is no-w acting in -a volume twice that in which it was acting in the arrangement of FIGURE 6(c), and therefore the forward speed of cross-'head 15 is one half of that for FIGURE 6(c). The area of piston over which the fluid now acts is twice that of the arrangement of FIGURE 6(0), and the force available to overcome the resistan-ce due to the workpiece is twice that available in the arrangement of FIGURE 6(c).

In order to avoid transient oscillations due to the elasticity of the oil and rams when changing from one of the arrangements of oil flow shown in FIGURE 6 to another of the arrangements the valves for exhausting the oil are delayed slightly in their opening period from the theoretical opening period until the stored elastic energy of the rams and oil has been sufficiently dissipated by movement of the crosshead to decompress the oil.

In order to aovid deflecting the workpiece after the forging stroke and just as the crossheads 15 commence their return stroke, the rams 65 are connected through equalising valves.

A principal advantage of the present invention is that separate independently operable means are employed for individual manipulating functions and such means are connected to the press structure. This contrasts with the previous practice of employing a so-called manipulator having `a peel for gripping the workpiece and capable of manipulation by rotation or longitudinal movement say to manipulate, in turn, the workpiece. The disadvantage of prior manipulators is that to effect longitudinal manipulation it has normally lbeen the practice to move the whole manipulator supported o-n a carriage for this purpose. Again since the workpiece is gripped throughout forging lby the manipulator, the manipulator is subjected to shock and is normally provided with shock absorbers, which again add to weight and inertia of the manipulator.

Also, as noted above the invention finds particular advantage in application to double-acting horizontal presses since the forging axis is substantially constant during forging, and the manipulation requirements for the ingot are accordingly reduced. Thus the equipment necessary in conventional single-acting forges for moving and repositioning the workpiece symmetrically with respect to the forging axis after each stroke of the crossheads, which axis varies with the workpiece thickness, can be dispensed with.

`Other advantages more particularly in the case of a horizontal unit lie in the low headroom and shallow foundations, 'both of which features improve the accessibility of all parts of the unit for maintenance. Furthermore, the ground area taken by a horizontal unit according to the invention is `sm-aller, since the tool changer can be disposed' beneath the forge instead of alongside, as in prior forges. Again, tool changing is more easily effected in the present unit than in prior units.

The forging apparatus according to the invention lends itself easily to automatic control, and ingots may be worked according to preselected programmes fed to electronic control means.

We claim:

1. An integrated forging apparatus comprising in combination:

means for supporting a workpiece in longitudinal disposition along a fixed substantially horizontal axis; a pair of press members mutually reciprocable in opposition about said axis to intermittently squeeze the workpiece;

manipulating means for moving the workpiece along said axis intermediate the squeezes by the press members, said manipulating means including at least one pair of gripping elements having convex surfaces facing the Iworkpiece for gripping the workpiece on opposite sides thereof; and

drive means for moving said gripping elements transversely of said axis into and out of gripping engagement with said workpiece and for angularly rotating said elements when in their gripping position to move the workpiece along said axis by a distance proportional to the angular movement of said elements.

2. A forging apparatus according to claim 1 comprising at least two pairs of said gripping elements similarly disposed relative to said axis and disposed one pair each on opposite sides of the line of action of the press members.

3. A forging apparatus according to claim 1 comprising, for each gripping element, a linearly acting first piston-and-cylinder assembly having a movable part and a stationary part, said stationary part being connected to the press framework, a rotary actuator having a movable part and a stationary part, said stationary part being connected to the movable part of the assembly, and the gripping element being connected at least to the movable part of the actuator for rotary motion, whereby the assembly is operable to urge the element into gripping contact with a workpiece and the actuator is operable to cause angular movement of the element.

4. A forging apparatus according to claim 1, wherein said manipulating means also includes at least one pair of gripping members disposed on opposite sides of said axis, means for urging the gripping members into gripping contact with a workpiece, means for imparting angular movement to the gripping members in a plane perpendicular to said axis to elect rotary manipulation of a Workpiece about its longitudinal axis by an angle equal to that of the gripping members angular movement, each said member having a keyed screw-form part with a threaded exterior threadably engaged in a captive nut-like device, and an annular toothed member rotatable about said axis and engaged with said devices whereby the gripping members are urged or withdrawn from gripping contact with a workpiece.

5. A forging apparatus according to claim 4 and including two pairs of gripping members disposed symmetrically about said axis.

6. A forging apparatus according to claim 4 and including rst drive means operably connectable to said annular toothed member to rotate the same in either direction about said axis, and second drive means operable to rotate said annular toothed member together with said gripping members and a workpiece gripped thereby about said axis.

References Cited UNITED STATES PATENTS 293,611 2/1884 Wood 72-420 383,142 5/1888 Nobs 72-421 1,392,328 10/1921 Heath 72-421 2,353,389 7/1944 Cannon 60-97 2,900,090 8/1959 Sack 72-420 2,916,952 12/1959 Schurman 72--337 3,126,770 3/1964 Wuppermann 72-420 3,177,696 4/ 1965 Hildebrandt 72-420 3,181,709 5/1965 Kinnicutt 214-1 3,209,578 10/1965 Muller 72-426 CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner. 

1. AN INTEGRATED FORGING APPARATUS COMPRISING IN COMBINATION: MEANS FOR SUPPORTING A WORKPIECE IN LONGITUDINAL DISPOSITION ALONG A FIXED SUBSTANTIALLY HORIZONTAL AXIS; A PAIR OF PRESS MEMBERS MUTUALLY RECIPROCABLE IN OPPOSITION ABOUT SAID AXIS TO INTERMITTENTLY SQUEEZE THE WORKPIECE; MANIPULATING MEANS FOR MOVING THE WORKPIECE ALONG SAID AXIS INTERMEDIATE THE SQUEEZES BY THE PRESS MEMBERS, SAID MANIPULATING MEANS INCLUDING AT LEAST ONE PAIR OF GRIPPING ELEMENTS, HAVING CONVEX SURFACES FACING THE WORKPIECE FOR GRIPPING ELEMENTS TRANSVERSELY OF SAID AXIS INTO AND OUT OF GRIPPING ENGAGEMENT WITH SAID WORKPIECE AND FOR ANGULARLY ROTATING VERSELY OF SAID AXIS INTO AND OUT OF GRIPPING ENGAGEMENT WITH SAID WORKPIECE AND FOR ANGULARLY ROTATING SAID ELEMENTS WHEN IN THEIR GRIPPING POSITION TO MOVE THE WORKPIECE ALONG SAID AXIS BY A DISTANCE PROPORTIONAL TO THE ANGULAR MOVEMENT OF SAID ELEMENTS. 